低温油藏深部调驱用弱凝胶体系研究

针对低温油藏深部调驱需要,在1%的醋酸铬溶液中,加入杀菌剂DQ、助剂DW,得低温交联剂,与聚合物混合均匀,30℃下反应,得有机弱凝胶。结果表明,在聚合物KYPAM2浓度为2 000～3 000 mg/L,聚合物/交联剂质量比为8∶1～10∶1,体系矿化度5 000～10 000 mg/L,30℃的油藏温度条件下,30 d后弱凝胶强度可达到10 000 mPa.s以上,未出现脱水、破胶的现象,并表现出良好的长期稳定性;在3 500×10-3μm2和560×10-3μm2填砂管组成的并联模型上,弱凝胶体系优先进入高渗通道,使后续流体转向进入低渗岩心,改善了非均质油藏开发效果。

Research of weak gel system for in-depth profile control in low temperature reservoirs

An organic crosslinking agent is prepared from bacterial DQ,assistant DW in 1% chromium acetate,then mixed with polymer,to obtain an orgainic weak gel at 30 ℃.The results showed that KYPAM2 concentration is between 2 000~3 000 mg/L,the polymer to crosslinking agent mass ratios between 8 ∶1~10 ∶1,system salinity between 5 000~10 000 mg/L,the cross-linked polymer system could gelate in 30 ℃ and the weak gel can keep high viscosity above 10 000 mPa·s in 30 d,meanwhile no gel dehydration and breaking is observed.On sets of 3 500×10-3 μm2 and 560×10-3 μm2 cores in parallel,the oil recovery and water-cut curves for every single core showed that the weak gel system enter preferentially into the higher permeability core and divert the fluid injected later into the lower permeability one,the weak gel can improve the development effect of the heterogeneous reservoirs.